assume cs:code
code segment
    start:mov ax, cs
          mov ds, ax
          mov si, offset s

          mov ax, 0
          mov es, ax
          mov di, 200h

          mov cx, offset se - offset s
          cld
          rep mov sb

          mov ax, 0
          mov es, ax
          mov word ptr es:[7ch * 4], 200h
          mov word ptr es:[7ch * 4 + 2], 0

          mov ax, 4c00h
          int 21h

       s:push bp
         mov bp, sp
         add ss:[bp+2], bx
         pop bp
         iret
        
       se:nop

code ends
end start
